The present invention relates generally to weaving machines, and in particular to system and method for controlling the sequence of stopping a plurality of weaving machines to minize the loss of time due to inevitable stoppages.
Owing to modern technological advances, the number of failures that occur in weaving machines has drastically reduced so that the number of maintenance personnels for a given number of machines has decreased. However, there are still some routine jobs done by the maintenance person which involves periodic stoppages of the machine to cut off the woven fabric to replace the cloth roller whenever the fabric has reached a predetermined length or supply a fresh roll of warp yarn whenever a predetermined amount of supply has been spent. It is the usual practice to operate the machines such that there is no overlapping between such routine jobs so as to minimize the outage times. In addition to the routine stoppage of the machine, the machine has to be stopped sometimes for fixing troubles such as failures in picking, warp yarn cutoff, and selvage yarn cutoff, although such failures have descreased in number. Since such stoppage actions occur at unpredictable times, particularly in respect of the actions caused by failures, routine stoppage actions are still likely to occur simultaneously with a failure stoppage action, and the number of such simultaneous occurrences tends to increase with the increase in the number of weaving machines to be controlled. From the standpoint of efficiency of machine operation and the number of maintenance personnels available, it is of course undesirable to allow the machines to stop simultaneously.
Weaving machine failures can be classified into a first group of failures which call for immediate action and a second group of failures which do not necessarily require such immediate action. Cutoffs in warp or selvage yarn belong to the first group of failures because a delay in the corrective action would result in an irrecoverable fault, while the failures in the second group includes failures in picking operation which does not necessarily call for immediate corrective action so long as such failure does not repeat itself within a short period of time. On the other hand, the routine-type stoppage actions can be deferred if a certain period of allowance is provided.